<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    .tab {
      width: 590px;
      height: 340px;
      margin: 20px;
      border: 1px solid #e4e4e4;
    }

    .tab-nav {
      width: 100%;
      height: 60px;
      line-height: 60px;
      display: flex;
      justify-content: space-between;
    }

    .tab-nav h3 {
      font-size: 24px;
      font-weight: normal;
      margin-left: 20px;
    }

    .tab-nav ul {
      list-style: none;
      display: flex;
      justify-content: flex-end;
    }

    .tab-nav ul li {
      margin: 0 20px;
      font-size: 14px;
    }

    .tab-nav ul li a {
      text-decoration: none;
      border-bottom: 2px solid transparent;
      color: #333;
    }

    .tab-nav ul li a.active {
      border-color: #e1251b;
      color: #e1251b;
    }

    .tab-content {
      padding: 0 16px;
    }

    .tab-content .item {
      display: none;
    }

    .tab-content .item.active {
      display: block;
    }
  </style>
</head>
<body>
  <div class="tab">
    <div class="tab-nav">
      <h3>每日特价</h3>
      <ul>
        <li><a class="active" href="javascript:;" data-id="0">精选</a></li>
        <li><a href="javascript:;" data-id="1">美食</a></li>
        <li><a href="javascript:;" data-id="2">百货</a></li>
        <li><a href="javascript:;" data-id="3">个护</a></li>
        <li><a href="javascript:;" data-id="4">预告</a></li>
      </ul>
    </div>
    <div class="tab-content">
      <div class="item active"><img src="./images/tab00.png" alt="" /></div>
      <div class="item"><img src="./images/tab01.png" alt="" /></div>
      <div class="item"><img src="./images/tab02.png" alt="" /></div>
      <div class="item"><img src="./images/tab03.png" alt="" /></div>
      <div class="item"><img src="./images/tab04.png" alt="" /></div>
    </div>
  </div>

  <script>
    //事件委托版tab栏
    //1.获取ul父元素 因为ul只有一个
    const ul = document.querySelector('.tab-nav ul')
    //获取5个 item
    const item = document.querySelectorAll('.tab-content .item')
    // 2. 添加事件
    ul.addEventListener('click',function (e) {
      //e.target是点击的对象
      // 我们只有点击了 a 才会 进行 添加类和删除类操作 
      if (e.target.tagName === 'A') {
        //排他思想 ，先移除原来的active  
        document.querySelector('.tab-nav .active').classList.remove('active')
        //当前元素添加 active  是 e.target
        // this 指向ul 不能用this 
        e.target.classList.add('active')

        // 下面大盒子模块
        const i = +e.target.dataset.id
        // 排他思想 ，先移除原来的active 
        document.querySelector('.tab-content .active').classList.remove('active')
        // 对应的大盒子 添加 active 
        items[i].classList.add('cative')
      }
    })
  </script>
</body>
</html>